Introduction: Liver transplantation (LTx) or Liver Kidney transplantation (LKTx) is proposed in methylmalonic acidemia (MMA) to restore sufficient enzymatic activity to avoid chronic symptoms and metabolic decompensation. We described the experience of a French pediatric reference center for metabolic diseases and LT/LKTx. Our aim was to determine whether Tx has a long-term impact on the patients’ quality of life.
Patients: Between 2004 and 2024, 33 patients with MMA received a Tx at Necker Hospital, 15 patients LTx and 18 combined LKTx. The median age at Tx was 7.9 years (1.4 - 18.5). The median follow up was 5.2 years (0.6 – 10.3).
Results: Four patients (27%) received a Tx from a living donor. Three patients (9%) died post-Tx of multiorgan failure. The median pre-Tx protein intake was 0.6 g/kg/d, 1 and 5 years post-Tx 1.2 g/kg/d and 1.3 g/kg/d respectively. Enteral nutrition was needed in 28 patients (85%) pre-Tx, in 8 only (27%) 1 year post-Tx, and none 5 years post-Tx. Significant reduction in the number of hospital admissions was observed, with a median of 5 per year pre-Tx, and one per year at 5 years. We observed a significant and sustained reduction in urinary methylmalonic acid (MMAc), less in LTx with living donors (heterozygous parent). Four patients developed Leigh syndrome, two immediately afterTx, and two one and four years later, as a result of acute dehydration. All recovered without sequelae. Five patients developed tremor, required a specific treatment, and also recovered. Improvement in the parents’ and child’s PedsQL score was seen, as well as in the Vineland score. No additional long-term cognitive impairment (WISC score) developed.
Conclusion: LTx and LKTx improve the long-term quality of life of patients with MMA, by liberalizing the diet, eliminate enteral nutrition and reduce the number of admissions. It also prevents long-term cognitive decline and improves Vineland and PedsQL scores. However, Tx does not completely protect against the risk of neurological complications, especially Leigh syndrome. No patient had long-term sequelae. Early Tx in MMA should be discussed, to protect patients from the risk of long-term neurological accidents and improve their development.